<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>图片自适应屏幕</title>
<style type="text/css">
#box{display:flex;top:0;left:0;width:100%;height:100%;background-repeat:no-repeat;background-size:100% auto;position:absolute;}
#box img{margin:0 auto;overflow:hidden;}
</style>
</head>
<body>
<div id="box">
	<img src="tupian.jpg">
</div>
</body>
</html>